1. Field of the Invention
The present invention relates to a two-dimensional motion producing apparatus for converting rotation of an input shaft to a two-dimensional motion in an X-direction of an output member and in an Y-direction orthogonal thereto.
2. Description of the Related Art
A conventional two-dimensional motion producing apparatus so far known is disclosed, for example, in Japanese Utility Model Publication No. Heisei 6-16365 (Int. Cl. G12B 5/00). This conventional apparatus is provided with two drive motors. This apparatus is constituted by a first arm provided on a rotational shaft of one drive motor, a second arm, a connecting plate and a first rail constituting a parallel crank mechanism together with the first arm, first and second sliders slidably provided on the first rail, a third arm provided on a rotational shaft of the other drive motor, and a second rail slidably mounted on a third slider provided on the third arm. The second rail is arranged at right angles to the first rail. The first and second sliders and the second rail are secured to a table as an output member.
One drive motor is driven to rotate the first arm whereby a moving force is applied to the table through the parallel crank mechanism so that the table is guided by the second rail and the third slider and moved linearly in the X-direction. On the other hand, the other drive motor is driven to rotate the third arm so that the table is guided by the first rail and the first and second sliders and moved linearly in the Y-direction. Accordingly, the two drive motors are driven so that the table can be moved linearly in the two-dimensional directions of X and Y.
However, in the conventional two-dimensional motion producing apparatus as described, it is necessary to provide two drive motors as drive sources. Further, in the conversion of the rotation of these drive motors to the movement in the two-dimensional direction of the table, it is necessary that the parallel crank mechanism constituted by a plurality of members such as the first arm, the second arm, the connecting plate and the first rail is connected to one drive motor. Further it is necessary to provide the first and second sliders for mounting the first rail on the table. On the other hand, in the other drive motor, it is necessary to provide the third arm, the third slider and the second rail mounted on the table.
Accordingly, the above-described conventional apparatus had various problems. Namely, it must have two drive sources. Very many constituent parts are required to convert from the rotation of the drive sources to the movement of the table in the two-dimensional direction. The construction is complicated, so there are many causes of occurrence of trouble so that it may deteriorate the durability. Since there involves the operation of the parallel crank mechanism, the high-speed operation of the apparatus is difficult to achieve.